The present invention relates to image projectors, and more specifically to image projectors having high intensity (brightness) and/or luminosity (total amount of light).
Most projection systems today uses ultra high pressure (UHP) lamps, e.g. Mercury arc lamps, with wattage from 120 W-350 W and a lifetime of typical 1500-4000 h. These projectors are compact and portable with brightness level of typical 1000-5000 lumens. Most of these projectors are single lamp solutions. These arc lamp projectors are typically for home or office use where the space is relatively small.
Projectors used for digital cinema, large venues, and for fixed installations have a typical brightness of 10,000-30,000 μm. These projectors typically use Xenon lamps with wattage range of 2-6 KW. However, a typical lifetime for a Xenon lamp is 500-1500 hours. Accordingly, the tradeoff is that the Xenon lamps have a shorter lifetime but a higher brightness (luminosity).
Thus, it is desirable to have projectors that use arc lamps to obtain a longer lifetime, that also provide the brightness of the Xenon lamps. Also, it may also be desirable to have Xenon projectors with even more brightness.
As previously mentioned, most of the image projectors use one lamp. To provide more brightness, image projectors do use multiple lamps. However, these lamps combine light from the multiple lamps in an inefficient manner. Typically, the light collection will be only typical 2 to 2.5 times a single lamp solution.
It is therefore desirable to multiple lamp systems that provide greater efficiency and brightness.